1. Field of the Invention
The invention relates to a power conversion technique, and relates to an inverting apparatus and an AC power system using the same.
2. Description of Related Art
In a general inverting apparatus used in an AC power system (such as a photovoltaic grid system, a wind power grid system, an uninterruptible power supply, or a back-up power system), often only effective power output can be provided, and ineffective power output compensation cannot be provided at the same time. Therefore, when the reactive power generated by the inverting apparatus is increased, the AC output voltage is increased as a result, such that crashing readily occurs to the inverting apparatus. As a result, the DC input power cannot be effectively converted into AC power for power supply, thus causing energy waste.
In current techniques, the inverting apparatus is provided with a sampling circuit of the AC output voltage so as to detect whether abnormality occurs to the AC output voltage. However, in all of the current inverting apparatuses, after the sampling circuit samples the voltage value of the AC output voltage, the voltage value needs to be outputted to a microprocessor in the inverting apparatus to perform a complex operation, such that the microprocessor can determine whether an overvoltage or undervoltage situation occurs to the AC output voltage. In other words, the microprocessor cannot instantly detect abnormality occurs to the AC output voltage. Moreover, since general sampling circuit designs are all too complex, the overall circuit design costs of the inverting apparatus are increased.